The following publications may be considered related technology to this invention:
R-1: T. H. James, "The Theory of the Photographic Processes," 4th Edition, MacMillan (1977). PA0 R-2: R. Doubendiek et al, "Multicolor Photographic Element With a Tabular Grain Emulsion Layer Overlaying a Minus Blue Recording Emulsion Layer," U.S. Pat. No. 4,693,964 issued to Eastman Kodak Company on Sep. 15, 1987. PA0 R-3: Anonymous, "Photographic Silver Halide Emulsions, Preparations, Addenda, Processing and Systems," Research Disclosure, 308, p. 933-1015 (1989). PA0 R-4: D. J. Beavers, "Photographic Diffusion Transfer Process, "U.S. Pat. No. 3,576,628 issued to Eastman Kodak Company on Apr. 27, 1971. PA0 R-5: Ishigaki et al, "Silver Halide Photographic Light Sensitive Material," U.S. Pat. No. 4,822,727 issued to Fuji Photo Film Co., Ltd., on Apr. 18, 1989. PA0 R-6: Y. Watanabe et al, "Process for the Production of Light-Sensitive Silver Halide Photographic Material, " U.S. Pat. No. 4,840,881 issued to Konishiroku Photo Industry Co., Ltd. on Jun. 20, 1989. PA0 R-7: A. Tanaka et al, "Color Photographic Materials Containing High-Boiling Organic Solvent," U.S. Defensive Publication T969,005 issued on Apr. 4,1978. PA0 R-8: H. Ota et al, "Silver Halide Photographic Light-Sensitive Material," U.S. Pat. No. 4,499,179 issued to Konishiroku Photo Industry Co., Ltd. on Feb. 12, 1985. PA0 R-9: P. Bagchi et al, "Photographic Element Having Polymer Particles Covalently Bonded to Gelatin," U.S. Pat. No. 4,855,219 issued to Eastman Kodak Company on Aug. 8, 1989. PA0 R-10: P. Bagchi et al, "Photographic Element Having Polymer Particles Covalently Bonded to Gelatin," European Patent Application 0 307 856, priority data Sep. 18, 1987, corresponding to R-9. PA0 R-11: P. Bagchi, "Gelatin-Grafted Polymer Particles," U.S. Application Ser. No. 307,393 allowed Dec., 1989. PA0 R-12: P. Bagchi, "Gelatin-Grafted Polymer Particles," European patent Application 0 037 855, priority date Sep. 18, 1987 corresponding to R-11. PA0 R-13: P. Bagchi, "Theory of Stabilization of Colloidal Particles by Nonionic Polymers," J. Colloid and Interface Science, 47, 86 (1974). PA0 R-14: P. Bagchi, "Nonionic Denting and Mixing Potentials Between Two Flat Plates," J. Colloid and Interface Science, 47, 100 (1974). PA0 R-15: D. S. Gibbs et al, "Structured Particle-Latexes," U.S. Pat. No. 4,017,442 issued to the Dow Chemical Company on Apr. 12, 1977. PA0 R-16: G. A. Campbell, "Crosslinkable Polymers Having Vinylsulfone Groups or Styrylsulfonyl Groups and Their Use as Hardeners for Gelatin," U.S. Pat. No. 4,161,407 issued to Eastman Kodak Company on Jul. 17, 1979. PA0 R-17: M. Oganer et al, "Element for Electrophonics," U.S. Pat. No. 4,548,870 issued to Fuji Photo Film Co., Ltd., on Oct. 22, 1985. PA0 R-18: H.L. Cohen et al, "Polymeric Mordants and Elements Containing Same," U.S. Pat. No. 3,625,694 issued to Eastman Kodak Company on Dec. 7, 1971. PA0 R-19: L. M. Minsk et al, "Polymeric Hardeners Containing Aziridinyl Units on the Side Chain," U.S. Pat. No. 3,671,256 issued to Eastman Kodak Company on Jun. 20, 1972. PA0 R-20: H. Jung et al, "Process for the Chain-Lengthening of Gelatin by Partial Hardening," U.S. Pat. No. 4,421,847 issued to Agfa-Gevaert on Dec. 20, 1983. PA0 R-21: J. Herzog, "Diphenyl-harnstoffchlorid als Reagens Fur Phenole," Chem. Ber. 40, 1831 (1907). PA0 R-22: W. Himmelman, "Hardening With a Heterocyclic Carbamoyl Ammonium Compound of a Photographic Material Containing a Silver Halide Layer," U.S. Pat. No. 3,880,665 issued to Agfa-Gevaert on Apr. 29, 1975, and German Application 2,225,230 dated May 24, 1972. PA0 R-23: W. Himmelman, "Hardening With a Heterocyclic Carbamoyl Ammonium Compound of a Photographic Material Containing a Silver Halide Layer," U.S. Pat. No. 3,880,665 issued to Agfa-Gevaert on Apr. 29, 1975, and German Application 2,317,677 dated Apr. 7, 1973. PA0 R-24: W. Himmelman et al, "Process for Hardening Silver Halide Containing Photographic Layer With Sulpho or Sulphoalkyl-Substituted Carbomoyl Peridinium Compounds," U.S. Pat. No. 4,063,952 issued to Agfa-Gevaert on Dec. 20, 1977, and German Application 2,439,551 dated Aug. 17, 1974. PA0 R-25: P. J. Stang et al, "Dication Ether Salts R.sup.+ --O--R.sup.+ --2CF.sub.3 SO.sub.3.sup.-, from the Reaction of Trifluoro-methane Sulfonic Anhydride With Activated Ketones," J. Am. Chem. Soc., 103, 4837 (1981). PA0 R-26: D. S. Morehouse et al, "Expandable Thermoplastic Polymer Particles Containing Volatile Fluid Foaming Agent and Method of Foaming the Same," U.S. Pat. No. 3,615,972 issued to the Dow Chemical Company on Oct. 26, 1971. PA0 R-27: W. R. Sorenson et al, "Preparative Methods of Polymer Chemistry," 2nd Edition, Wiley (1968), N.Y. PA0 R-28: M. P. Stevens, "Polymer Chemistry--An Introduction," Addison Wesley (1975), London. PA0 R-29: H. G. Curme et al, "The Adsorption of Gelatin to a Silver Bromide Sol," J. Phys. Chem. 68, 3009 (1964).
Pressure applied to photographic emulsion coatings can produce both reversible and irreversible effects on the sensitometry of the photographic product. Sufficient pressure can cause irreversible distortion of the emulsion grains or cause the formation of physical defects that alter the sensitivity for latent image formation. It has been generally recognized (R-1) that effect of pressure on the sensitivity of photographic products increases with the magnitude of the applied pressure.
Various types of pressure effects on silver halide photographic systems have been known for long periods of time. In general, pressure sensitivity can be described as an effect which causes the photographic sensitometry of film products to change after the application of some kind of a mechanical stress to a coated photographic film.
The cited prior art (R-1) describe various mechanisms in association with the various types of pressure sensitivities observed with photographic products. However, one observation in all of the described cases, is clear that the change in sensitometry is caused by the transmission of physical stress to the silver halide crystals.
In photographic systems, pressure sensitivity, as described, in this general term produces considerable quality defects of products that manifest as increased or decreased density marks on them after development. Such stress may be received from transport mechanism in cameras or other exposing devices or possibly during processing operations. In general, the pressure sensitivity problem increases with the physical size of the emulsion crystals. Its manifestation is most severe in the high aspect ratio highly deformable "Tabular Grain Emulsions," extensively described in prior art (R-1, R-2, and R-3). There is, therefore, a need to produce photographic coatings that are less sensitive to mechanical stress in order to improve the quality of many of the current photographic products.
Dry gelatin is hard and can thus easily transmit applied stress to the silver halide crystals in a coated photographic system. Prior arts (R-4 and R-5) describe the inclusion of low glass transition temperature, Tg, soft polymer latexes into coated photographic films. (R-4) discloses inclusion of such polymers into the emulsion containing layers, and (R-5) describes incorporation of such polymers into overcoat layers. Inclusion of polymers as described in (R-4 and R-5) does tend to reduce pressure sensitivity of photographic film products. Present day photographic products have higher and higher photographic speeds and consequently are larger and larger in dimension and exhibit more severe pressure sensitivity problems. In order to reduce the pressure sensitivities of present day silver halide photographic products, the amounts of soft latex load necessary as described in prior art (R-4 and R-5) are so large that such films with high polymer latex loads suffer from severe developability problems due to the coalescence of the soft polymer particles in the dry coated layers, where a large portion of the gelatin has been replaced by soft polymer latexes. Similarly, prior art (R-6, R-7, and R-8) describe the use of organic solvent dispersions in photographic layer to reduce the pressure sensitivities of film products. however, in order to reduce the pressure sensitivity of present day high speed and high pressure sensitivity photographic products, the solvent loads of the films have to be so high that such films show signs of delamination in the layers containing the solvent dispersion when pressure is applied for testing. Therefore, it would be desirable to reduce pressure sensitivity of photographic products without inhibiting developability or diminishing the integrity of film product.